Heat-exchange device



May 13, 1924. 1,494,245

E. .1. HUBBERT HEAT EXCHANGE DEViCE Filed Nov 6, 1925 3 Sheets-Sheet awvem E. JZZ'ZLMBI'Z' May 13 924.

E. J. HUBBERT HEAT EXCHANGE DEVICE Filed Nov. 6, 1923 5 Sheets-Sheet 3 Elvwemboz E. Jliubberl Q zuzwmdma E.J.HUBBERT HEAT EXCHANGE DEVI CE Filed Nov. 6, 1923 3 Sheets-Sheet 5 Patented May 13, 1924.

UNITED STATES ERNEST J. HUBBERT, 0F BILLINGS, MONTANA.

nm'r-nxcnancn nnvrcn Application filed November 6, 1923. Serial 1%. e'za,171.

To all whom it may concern:

Be it known that I, ERNEST J. HUBBERT, a citizen of the United States, residing at Billings, in the county of Yellowstone and State of Montana, have invented certain new and useful Improvements in Heat-Exchange Devices, and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention relates to improvements in waste heat device for furnaces and the like in which the heat usually lost through the stack is recovered in a large measure and applied to the preheating of the cold air.

It is a well known fact among heating engineers that only about 50% of the heat generated from combustible fuel in the average appliance is absorbed and trans? mitted to its actual station of usefulness. This applies more particularly to domestic house heating appliances, and especially to hot air furnaces.

When the coal. burning furnace is converted to natural gas the average efficiency is around leaving 40% to be wasted through the chimney into the atmosphere.

The difliculty is almost entirely traceable to the lack of heat absorbing surface or metal walls that will pick up the heat after combustion has taken place so these units can be carried by circulation through channels intended to convey them to the different points of utility. It is with the purpose in mind of adding additional absorbing surface and travel to the hot air furnace and arresting the waste heat by passing it over sheet iron walls, and inturn passing the air circulation over these elements which by gravitation returns them to the dome of the furnace for redistribution.

It is an object of the invention to produce a device of simple construction. inexpensive to make commercially and of compact design whereby it may be coupled to the usual heating systems without re uiring any alteration therein, except possi ly in the rearranging of piping; the device being adapted to receive the heat products passing through the smoke pipe, through which the device is included, an for causlng these products to give up to the cold air which is circulated through the device a large degree of the heat which is usually dissipated.

WVith the foregoing and other objects in view, the invention will be more fully described hereinafter, and will be more particularly pointed out in the claims appended hereto. 7

In the drawings, wherein like symbols refer to like or corresponding parts throughout the several views,

Figure 1 is a side view of a furnace and draft and heating pipes with the invention installed in connection therewith.

Figure 2 isa top plan view, with parts broken away, of the improved device.

Figure 3 1s a central vertical section taken on the line 3'3 in Figure 2.

Figure 4 is an end view ofFigure 3 taken from the left as shown in Figure 2.

Figure 5 is a cross section taken on the line 55 in Figure 2, and

Figure 6 is a longitudinalsection taken on the line 6-6 in Figure 3.

Referring more particularly to the drawings, and for the present to Figure 1, 7 designates a furnace having a number of pipes 8 for conveying the heat therefrom to the rooms of a building to be heated or to destinations of use. The furnace is further provided with a smoke pipe 9 connecting with the chimney 10 and acold, air pipe 11 is shown as connecting with the base ofthe furnace.

In accordance with the invention the improved device indicated at 12 is coupled in the smoke pipe 9 and is actually connected with the smoke zone of the furnace by the pipe section 13. The device is further connected with the dome of the furnace by the pipe 14 having the damper 15 and with the heat conveying pipes by the ipe section 16 having the damper 17 Cold air, for instance from the pipe 11, is introduced into the device by means of the pi e section 18.

As shown more particular y in Figures 2 to 6 inclusive, the improved device is comprised within the shell or casing previously referred to as 12 and being of substantially rectangular form in cross section as indicated in Figure 5. except that at the u )per portion the shell or casing is curve or arched to a central high point. The casing is closed by heads 19 and '20 suitably afiix ed therein. The head 19 is perforated to receive the pipes 13 and 14 and the pipe 14 cold air space 25 from the hot air circulating chamber 27. The false bottom 26 is provided with spaced rows of erforations 28 extending in a longitudinal direction and being enveloped by the base portions of the channels 22. The channels extend upwardly from the perforated false bottom 26 in substantial parallelism and the channels are spaced apart, preferabl a uniform distance, providing spaces there etween for the circulation of thesmoke and hot waste products from the furnace. The upper ends of the tubular channels, or rather the plates 23 and 24, which constitute and provide these channels, are curved mutually toward the tube 21 at their upper ends and in conformity with the arched dome like top of the casing 12, the tubular channels communi eating with the tube 21 and delivering the air thereto after passage through the channels. The tube 21 is thus perforated to receive the upper ends of the plates 23 and 24 but the imperforate portions of the tube 21 between the points of the connection prevent any access of the smoke or waste heat products from the furnace from actually getting into the tube 21. The tubular channels 22 are closed at their ends by strips 29 and 30, and the various parts may be welded or secured together in any desired manner. The parts are, moreover, preferably formed of sheet metal of desired thickness, but I do not wish to be restricted to this material alone, as it is quite possible to make the device from other material and any other va rious sizes and shapes. The smoke pipe 51 connects with the head 20 by means of the cone 31 in order to condense the products and direct them into the smoke pipe.

In the use of the device, the casing is coupled as shown in Figure 1, and the furnace being in operation, smoke and the other heat products will pass through the device on the way to the chimney. The heat in these products is customarily wasted, but in entering the device through the pipe 13, such normally wasted heat products will pass through the spaces 27 from end to end of the casing 12 and will be brought into active contact with the long plates 23 and 24 which confine the narrow channels 22. The heat products will then seek exit through the cone 31 and. smoke pipe 9, but they will be received in a much cooler condition, and after they have given up a large per cent of their heat to the cold air which enters the base of the casing 12 by means of the cold air pipes 11 and 18. The cold air will ascend through the perforations 28 and the channels 22 and will create a considerable draft as this cold air becomes heated in the channels and rises into the tube 21. From this tube the heated air is delivered by the pipe 14 to the furnace dome or by the pipe 16 to the heat conveying or distributing pipes directly. By ad justing the dampers 15 and 16 the'heated air from the device 12 may be diverted to either destination as required. By cold air regulation with a damper, such as 32 in the cold air pipe, the stack temperatures can be reduced to a minimum thus effecting a saving of practically all the available heat units. The excess waste heat products of combustion are exhausted through pipe 9 and into the stack or chimney.

The invention will be found particularly adapted to heating plants where natural gas is used, but no doubt it will give equally good results where coal, or other fuel is employed.

It is obvious that various changes and modifications may be made in the details of construction and design of the above specifically described embodiment of this invention without departing from the spirit thereof, such changes and modifications being restricted only by the scope of the following claims.

What is claimed is:

1. A device as described comprising a casing, heads in the ends thereof. sections of a furnace smoke pipe coupled through opposite heads, a tube at the upper portion of said casing, a perforated false bot-tom spaced above the true bottom of the casing and providing an air space thcrebetwcen in communication with a source of'cold air supply, plates secured at opposite sides of the perforations of the false bottom and providing channelstherebetween communicating with the tube, a pipe connecting with the tube and the dome of the furnace. and a second pipe connecting with said tube'and directly with points of use.

2. A device as described comprising a casing having an arched top portion, a head secured in the casing, sections of a smoke pipe connected with opposite head. a tube in the upper portion of the casing. air channels connected at their upper ends with said tube and being curved mutually at opposite sides to conform to the arched top of the casing, an air chamber at the base of said casing in communication with the lower ends of said channels, said channels being spaced apart.

ERNEST J. HUBBERT. 

